Resuspension of particles relevant as viruses can remain viable for extended periods

ebolaSuspension and shedding require persistent cleaning. Viruses can hang around and be viable even three hours after being generated, making resuspension of particles a matter of concern. Droplets from sneezes might travel farther than the Center for Disease Control has suggested, too. Below are some studies that detail some of this.

Comparison of the Aerosol Stability of 2 Strains of Zaire ebolavirus From the 1976 and 2013 Outbreaks is a study that shows “the viability of 2 Zaire ebolavirus strains within aerosols at 22°C and 80% relative humidity over time. The results presented here indicate that there is no difference in virus stability between the 2 strains and that viable virus can be recovered from an aerosol 180 minutes after it is generated.” Think about this in the context that all particles can be aerosolized, and the new study from MIT that films droplets moving 6-8 meters vs. the CDC droplet precaution of three feet.

An evaluation of the impact of flooring types on exposures to fine and coarse particles within the residential micro-environment using CONTAM notes that flooring type significantly impacts the extent to which particulate matter (PM) exposures are elevated indoors from particle resuspension. Hardwood floors were identified as the most effective flooring type for the reduction of (daily, 24-h) incremental time-averaged exposure to either fine or coarse particles due to resuspension while walking.

Surrounded by a Cloud of Dust: Particle Resuspension in Indoor Environments is an informative YouTube piece presented by Brandon E. Boor, Ph.D. Assistant Professor of Civil Engineering, Purdue University at a gathering of the National Academy of Sciences, Engineering and Medicine.


Copper has its limits as antimicrobial agent as resistance grows

copperStudies show again and again what all pharmacists and microbiologists already know: Bacteria build immunity to antibiotics, pesticides and disinfectants, rendering them largely ineffective over time. Below are some studies that discuss the use of copper as an antimicrobial.

Characterization of Copper Resistance in Acinetobacter baumannii points out that Acinetobacter baumannii causes many types of severe nosocomial infections and that some isolates have acquired resistance to almost every available antibiotic, limiting treatment options. Copper is an essential nutrient, but becomes toxic at high concentrations. The inherent antimicrobial properties of copper give it potential for use in novel therapeutics against drug resistant pathogens. We show that A. baumannii clinical isolates are sensitive to copper in vitro, both in liquid and on solid metal surfaces. Since bacterial resistance to copper is mediated though mechanisms of efflux and detoxification, we identified genes encoding putative copper-related proteins in A. baumannii and showed that expression of some of these genes is regulated by copper concentration. We propose that the antimicrobial effects of copper may be beneficial to development of future therapeutics that target multidrug resistant bacteria.

Bacterial resistance to copper in the making for thousands of years suggests that genetic changes pose risks to human immunity. Published at The Ohio State University website, Misti Crane writes that more copper in the environment leads to more bacteria, including E. coli that develops a genetic resistance.

Characterization of copper-resistant bacteria and bacterial communities from copper-polluted agricultural soils of central Chile suggests that “bacterial communities of agricultural soils from central Chile exposed to long-term copper (Cu) pollution have been adapted by acquiring Cu genetic determinants. Five bacterial isolates showed high copper resistance and additional resistance to other heavy metals. Detection of copA gene in plasmids of four Cu-resistant isolates indicates that mobile genetic elements are involved in the spreading of Cu genetic determinants in polluted environments.”